Small portable containers for gas under pressure have been used for inflating automobile tires in an emergency. Such containers, one form of which is disclosed in U.S. Pat. No. 2,498,596, have a dispensing head with a passage that is normally closed by a high pressure tire valve core. When a tire is to be inflated, the dispensing head is attached to the tire valve stem to cause the tire valves in both the stem and in the dispensing head to open whereby the gas passes from the container into the tire. Similar containers for dispensing gas under pressure have also been used for other purposes. For example, U.S. Pat. No. 3,570,714 discloses a device for dispensing oxygen for medical purposes. It likewise uses a conventional tire valve to normally close a passage leading from the container. There is also a check valve between such tire valve and the interior of the container. This check valve has a small orifice through which the oxygen must pass to prevent too rapid discharge from the container.
These and other prior devices for dispensing gas under pressure from a container utilize moving parts that may become jammed and do not make adequate provision to discharge the gas from the container when unthreading the dispensing head whereby pressurized gas still in the container when the head is completely unthreaded therefrom may blow the head away from the container and cause bodily harm or other damage.